The Living Cosmos

Our Search for Life in the Universe

Chris Impey, Central 576.839 I34L 2007, Random House

A bit dated, a few howlers, skimmed.

p151 "Slightly later, and you would have plowed into the Asteroid Belt and been ground into harmless boulders."

• er, no. even in the ecliptic plane, the asteroid belt is sparse enough to be almost transparent. There are certainly enough "vermin of the sky" asteroids to leave light tracks through long-duration sky exposures, but a similarly long time exposure of a rural highway around 2 am would show enough headlight streaks to make the road seem bumper-to-bumper, even if cars actually only pass once every 20 minutes. The asteroid belt is vastly less bright than the full Moon, hence the steradians of the sky it occults is less than the Moon's 1e-5, so its collision cross section is vastly smaller than that fraction. A comet passing through the asteroid belt is less likely to collide with any asteroid than you are, at home in bed. In the vanishingly small chance that an asteroid /did/ hit one or two or ten asteroids, it might be smashed into small and large fragments, but the largest fragments would be potential city killers, not "harmless boulders".

p160 a graph of hypothetical radiation flux (not actual data) from solar flares and distant stellar "cataclysms" over the last 4.5 billion years, attributed to John Scalo at the University of Texas (Austin). This may have been presented at an astronomical meeting, but I cannot find it in papers by Scalo between 1995 and 2005. I'd sure like to see Scalo's methods for producing this graph, and I would love to see a citation of a Scalo paper in Impey's book, so I can look for evaluations of that paper by others.

p190 Impey doesn't seem to understand the Rare Earth argument, and he imputes motivations to Ward and Brownlee's work that are missing from the book and the authors themselves. We have since come across many more additional factors that add to the "rareness" question:

• The complete absence (so far) of planetary systems that have planetary distributions and near-circular orbits like ours. Granted, that may be due to the relative unobservability (no hot Jupiters, for example) of planetary systems like ours.
• The aluminum-26 pulse that accompanied the formation of our solar system. Perhaps I misunderstand Harold Urey's work on meteorite isotopes, but the implication is that the solar system condensed into grains while new Aluminum 26 isotopes were being deposited, implying that this arrived from a second supernova shock time after the first one that triggered the collapse of the prestellar cloud.

  • NOTE 2019 - the solar system most likely formed in the bubble of a Wolf-Rayet star, according to the Origins project at the University of Chicago in 2017 )

• The singular (and delayed) evolution of eukaryotes. Many of the events that resulted in complex life might have happened sooner ... or later ... or never at all. These are NOT easy steps.
• The "late" appearance of humans in the history of life, following the "fortuitous" extinction of dinosaurs, following the relatively recent appearance of land life.
• With a sample of one, and a sample of zero detectable intelligence elsewhere, it is presumptuous to make ANY statements about the frequency of intelligent life - or the wisdom of spending valuable resources looking for it, when we don't know what we are looking for. Finding /life/ at the molecular level is more scientifically and economically useful. And avoiding "the Great Filter" is essential.

p195 "water in the recent past." The Mars Global Surveyor images that were interpreted as "gullies and runoff channels" are also what bone-dry dust does, as recent (2017) papers claim.

p202 Richard Mathies at UCB, biolab on silicon chip 1000x more sensitive to amino acids.

• PNAS 2005 "... Mars Organic Analyzer (MOA), a microfabricated capillary electrophoresis (CE) ..."

• Chromatography A 2003 Chiral separation of fluorescamine-labeled amino acids using microfabricated capillary electrophoresis devices for extraterrestrial exploration

Mars contamination briefly addressed by note 15 on page 330, mentions 1967 UN treaty and NASA's planetary protection officer.

Note 20 page 314 "Atomic clocks flown at high altitude actually tick slower than identical clocks at sea level." NO, it goes the other way.

... etc. I don't have time to wade through the rest, especially given the lack of tracable citations so I can look for forward connections to recent research.

Overall, I was hoping for more from the time I spent on this book, including better editing and fact checking. Dr. Impey's newer books seem better.